Mobile KTV ordering machine circuit based on PPTC self-restoring fuse

Abstract

The utility model relates to electronic circuit technical field especially relates to a mobile KTV song ordering machine circuit based on PPTC self -restoring fuse belongs to electronic circuit protection technical field. The circuit is in series first self -restoring fuse (PPTC1) between power input interface (K1) and charge -discharge management circuit, is in series fourth self -restoring fuse (PPTC4) on lithium battery loop, and is in series multiple self -restoring fuse (PPTC2, PPTC3, PPTC5-PPTC9) respectively in power conversion circuit output end and the power input end of each function module (such as touch -sensitive screen, LCD screen, audio power amplifier, USB interface etc.). The utility model uses PPTC self -restoring fuse as core protection element, realizes overcurrent, short circuit and overtemperature protection to song ordering machine each key node with the simplest circuit structure, has the advantages such as few component quantity, low cost, high reliability, need not maintenance, can automatically restore, significantly improves the safety, reliability, and stability of mobile KTV song ordering machine.

Description

Technical Field

[0001] This utility model relates to the field of electronic circuit technology, and in particular to a mobile KTV karaoke machine circuit based on a PPTC self-resetting fuse. Background Technology

[0002] Existing mobile karaoke machines mostly use traditional fuses or multi-component protection circuits for circuit protection, which have problems such as many components, large size, high cost, poor reliability, and difficult maintenance. Traditional fuses are mostly single-use and need to be replaced manually after failure. They are also slow to react in the event of short circuits or overcurrents, which can easily lead to circuit damage or even safety hazards such as lithium battery explosion. Utility Model Content

[0003] The purpose of this invention is to provide a mobile KTV karaoke machine circuit based on a PPTC self-resetting fuse, which is a simple, reliable, low-cost, and self-resetting circuit protection system.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: a mobile KTV karaoke machine circuit based on a PPTC self-resetting fuse, comprising a power input interface (K1), a charge / discharge management circuit, a lithium battery, a power conversion circuit, and multiple functional modules; a first self-resetting fuse (PPTC1) is connected in series between the power input interface (K1) and the charge / discharge management circuit; a fourth self-resetting fuse (PPTC4) is connected in series in the charge / discharge circuit of the lithium battery; and multiple self-resetting fuses (PPTC2, PPTC3, PPTC5-PPTC9) are connected in series at the output terminal of the power conversion circuit, the power input terminal of each functional module, and the output circuit of a specific functional module.

[0005] As a further improvement of this utility model, a varistor (RV) is also connected in parallel at the rear end of the power input interface (K1), and the varistor (RV) works in conjunction with the first self-resetting fuse (PPTC1) to achieve overvoltage protection.

[0006] As a further improvement of this utility model, the plurality of functional modules include at least one of the following: MCU and encoding / decoding circuit, LCD screen and driving circuit, touch screen and driving circuit, audio power amplifier circuit, I / O and interface driving circuit, Bluetooth circuit, and storage module.

[0007] As a further improvement of this utility model, the third self-resetting fuse (PPTC3) is connected in series in the power path of the USB interface.

[0008] As a further improvement of this utility model, the fifth self-resetting fuse (PPTC5) is connected in series in the power path of the touch screen driver circuit.

[0009] As a further improvement of this utility model, the sixth self-resetting fuse (PPTC6) is connected in series in the power path of the LCD screen driving circuit.

[0010] As a further improvement of this utility model, the seventh self-resetting fuse (PPTC7) is connected in series in the power path of the audio power amplifier circuit.

[0011] As a further improvement of this utility model, the eighth self-resetting fuse (PPTC8) is connected in series in the power path of the I / O and interface drive circuit.

[0012] As a further improvement of this utility model, the ninth self-resetting fuse (PPTC9) is connected in series in the circuit between the tweeter and the audio power amplifier circuit.

[0013] As a further improvement of this utility model, the self-resetting fuse (PPTC1-PPTC9) is a surface mount package.

[0014] The beneficial effects of this utility model are:

[0015] 1. The use of PPTC self-resetting fuses to replace traditional multi-component protection circuits significantly reduces the number of components and simplifies the circuit structure;

[0016] 2. It has multiple protection functions including overcurrent, short circuit, and over-temperature, with rapid response and high reliability;

[0017] 3. It can automatically recover after protection, requiring no manual replacement and resulting in low maintenance costs;

[0018] 4. Small size and low cost, suitable for portable devices, improving product safety and market competitiveness. Attached Figure Description

[0019] Figure 1 This is a block diagram of the circuit system of this utility model. Detailed Implementation

[0020] To facilitate understanding of this utility model, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of this utility model are shown in the drawings. However, this utility model can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this utility model.

[0021] It should be noted that when a component is said to be "fixed to" another component, it can be directly attached to the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0023] Please see Figure 1 This utility model discloses a portable KTV karaoke machine circuit based on PPTC self-resetting fuses. By setting multiple self-resetting fuses, overcurrent, short circuit, and over-temperature protection are achieved for the corresponding circuits, and the circuit automatically recovers after the fault is cleared. Specifically, it includes:

[0024] The power input interface (K1) is used to connect an external DC 15V power supply;

[0025] The charge and discharge management circuit is connected to the lithium battery and the device's main power supply (e.g., 12V) to manage the charging and discharging process of the lithium battery.

[0026] The power conversion circuit converts the lithium battery voltage into multiple DC voltages (such as 12V, 5.0V, 3.3V);

[0027] And multiple functional modules; including MCU and encoding / decoding circuits:

[0028] LCD screen and driving circuit: display interface and its driving;

[0029] Touchscreen and driver circuit: Touch operation and its driving;

[0030] Audio power amplifier circuit: audio signal processing and power amplification;

[0031] I / O and interface drivers: manage various input / output interfaces;

[0032] Bluetooth circuit: wireless communication module;

[0033] Storage module, 2TB digital hard drive, for storing song data, etc.;

[0034] A first resettable fuse (PPTC1) is connected in series between the power input interface (K1) and the charge / discharge management circuit, located at the DC15V power input terminal, to protect the charge / discharge management circuit and the varistor RV. A fourth resettable fuse (PPTC4) is connected in series in the lithium battery charge / discharge circuit to specifically protect the lithium battery and prevent thermal runaway caused by overcharging, over-discharging, or short circuits. Multiple resettable fuses (PPTC2, PPTC3, PPTC5-PPTC9) are connected in series at the output terminal of the power conversion circuit, the power input terminal of each functional module, and the output circuit of a specific functional module. Once a module is short-circuited or overcurrent occurs, the corresponding PPTC is triggered for protection, isolating the fault.

[0035] A varistor (RV) is connected in parallel at the rear end of the power input interface (K1). The varistor (RV) works in conjunction with the first resettable fuse (PPTC1) to achieve overvoltage protection, which is used to absorb surge voltage and suppress high voltage pulses.

[0036] Multiple functional modules include at least one of the following: MCU and encoding / decoding circuit, LCD screen and driver circuit, touch screen and driver circuit, audio power amplifier circuit, I / O and interface driver circuit, Bluetooth circuit, and storage module.

[0037] The third resettable fuse (PPTC3) is connected in series in the power path of the USB interface to prevent damage caused by improper insertion or removal of the USB flash drive or short circuit of the peripheral device.

[0038] The fifth resettable fuse (PPTC5) is connected in series in the power path of the touch screen driver circuit to prevent the spread of short circuit faults caused during production or use.

[0039] The sixth resettable fuse (PPTC6) is connected in series in the power path of the LCD screen driving circuit to prevent damage from high current caused by short circuit due to resonance in the high-frequency driving circuit.

[0040] The seventh resettable fuse (PPTC7) is connected in series in the power path of the audio power amplifier circuit to provide overcurrent and short-circuit protection for the power amplifier chip and its related circuits.

[0041] The eighth resettable fuse (PPTC8) is connected in series in the power path of the I / O and interface driver circuits (such as HDMI, VGA, RJ45, etc.) to prevent abnormal current introduced by hot-plugging of interfaces or failure of external devices.

[0042] The ninth resettable fuse (PPTC9) is connected in series in the circuit between the tweeter and the audio amplifier circuit. It can effectively suppress the increased current caused by microphone feedback and protect the speaker voice coil and the amplifier circuit.

[0043] like Figure 1 The diagram illustrates the overall circuit topology of this invention, wherein...

[0044] PPTC1-PPTC9 are strategically placed in the power paths of key circuits, forming a multi-layered, distributed protection network to ensure that a fault in any single branch will not affect the safety of the entire system. All PPTCs are connected in series on the power lines. Since all current and voltage changes are reflected on the power lines, the components connected before and after each PPTC are included in the block diagram. It is unnecessary to show the specific connected components of the PPTC or to present a complex schematic diagram, making the circuit simple, intuitive, and easy to describe and read. A DC 15V power supply is input through the power input interface K1, and then connected to the charge / discharge management circuit and PPTC4 through the first self-resetting fuse PPTC1 and the varistor RV to charge the 12V lithium battery. Simultaneously, the charge / discharge management circuit supplies power from the lithium battery to the power conversion circuit through PPTC2. The power conversion circuit outputs three channels: DC 12V, DC 5.0V, and DC 3.3V, supplying power to the corresponding functional circuit modules. When an external high voltage or short circuit occurs, PPTC1 provides current limiting protection, and RV is protected from breakdown. Each functional module's power input terminal is connected in series with PPTC2 to PPTC9 to achieve independent protection for critical circuits. PPTCs operate at low resistance under normal conditions, not affecting circuit operation; when overcurrent, short circuit, or overtemperature is detected, they quickly switch to high resistance to limit current and protect the circuit and lithium battery; they automatically reset after the fault is cleared.

[0045] The resettable fuses (PPTC1-PPTC9) are surface-mount packages using a 1206 package. When there is overcurrent, short circuit, or overtemperature, the resistance value changes abruptly from the mΩ level to the kΩ level to achieve current limiting protection; after the fault is cleared, they automatically return to the low resistance state.

[0046] When the user plugs or connects other high-voltage adapter power supplies (such as 24V, 36V, 48V, 60V, or other high voltages) into or in series with interface K1, the varistor RV will be triggered and conduct for a brief short circuit within about 10ns. This prevents the high voltage from being transmitted to subsequent circuits and causing damage. However, after the varistor conducts and short-circuits, it not only short-circuits the external high voltage but also the power output terminal, generating a large current of 100 amperes or more. The varistor would explode within 1 second. But now, with the self-resetting fuse PPTC1 in front, this large current will also pass through PPTC1. At this time, because PPTC1 changes its resistance value abruptly to a high resistance under the action of this large current, it limits the large current and protects RV. This prevents the varistor RV from overheating and exploding. Moreover, RV can be reused. In this design application scheme... The PPTC1 resettable fuse protects the entire system by protecting the varistor RV. Once the high current disappears, the PPTC1 automatically returns to its initial low resistance value, preventing damage to the mobile karaoke machine system. The PPTC4 resettable fuse is designed for lithium battery protection. When overcurrent or short circuits occur in the charge / discharge management circuit, or when overcurrent occurs in the power supply circuit or other load circuits, the PPTC4 changes from low resistance to high resistance to provide timely current limiting protection for the lithium battery, preventing overheating and explosion under high current. It also limits the high current in related circuits, thus protecting the entire system circuit. The PPTC2 resettable fuse also changes from low resistance to high resistance to achieve current limiting protection when there is a short circuit in the power conversion circuit or overcurrent in related circuits. PPTC3 is designed to protect the power conversion circuit of a USB interface when an external device or USB flash drive is misaligned and short-circuited, thus protecting the external USB device or flash drive as well. Similarly, PPTC5 is designed for short-circuit protection of the touchscreen circuit. Due to the compact design of touchscreen circuits, short circuits can easily occur during production, such as solder short circuits, PCB copper short circuits, and component misalignment short circuits, which can easily generate large short-circuit currents. In such cases, PPTC5 will suddenly change from low resistance to high resistance to limit the current for protection. Without the protection circuit of the PPTC5 self-resetting fuse, this would not only burn out the touchscreen circuit components, but also burn out the related components of the power conversion circuit, or cause the lithium battery to over-discharge and be damaged through the charge and discharge management circuit, or even cause the lithium battery to overheat and explode. With the PPTC5 self-resetting fuse, the relevant circuits can be effectively protected by limiting the current in a timely manner, and a series of related problems can be avoided. Similarly...

[0047] PPTC6 is designed to protect the LCD screen's driver circuit. Because the MOSFETs and resistors / capacitors in the driver circuit are surface-mount devices with high operating frequencies, they are prone to resonance due to variations in their distributed parameters and self-generated RC inductance. This can instantaneously generate a high voltage several times the power supply voltage, causing the MOSFET to short-circuit and resulting in a large current. In this situation, PPTC6 abruptly changes from its normal low resistance to a high resistance to limit the current, protecting the connected MOSFET and related components in the power conversion circuit. PPTC6's current-limiting protection also protects the entire system circuit, effectively preventing large-area damage caused by partial short circuits. Simultaneously, the high resistance of the protected circuit isolates the faulty circuit, preventing passive damage to other circuits. Similarly, PPTC7 is a power supply protection circuit for audio amplifiers in case of a short circuit. When the amplifier experiences overcurrent or a short circuit, PPTC7 abruptly changes from low resistance to high resistance to achieve current-limiting protection. While PPTC7 is performing its current-limiting protection function, it also protects the power supply and the amplifier circuit containing PPTC7. Similarly, PPTC8 is designed to protect the power supply... In I / O and interface driver circuits, when a short circuit or overcurrent occurs, the PPTC8 will abruptly change from its normal low resistance to high resistance to limit the current and protect the circuit. When the power is off or the circuit returns to normal, the PPTC8 will return from high resistance to its normal low resistance state. This interface driver circuit itself, as well as the HDMI and RJ45 interfaces, are prone to circuit problems. Without timely protection, not only will more components be damaged, but it may also burn out related components in the power conversion circuit, leading to a series of problems such as damage to the lithium battery. Therefore, the PPTC8 can effectively avoid many known and unpredictable problems. The PPTC9 is designed for tweeter protection. Because microphones may produce howling at a certain high frequency, the howling current can rapidly increase and burn out the tweeter. With the PPTC9, the sudden change to high resistance under high current limits this high current and effectively protects the tweeter and power amplifier circuit. When the howling stops and the current drops to normal, the PPTC9 will return from high resistance to low resistance, making the power amplifier and tweeter less prone to damage.

[0048] The overcurrent, short-circuit, and over-temperature protection functions are achieved using PPTC self-resetting fuses, which are implemented by a single PPTC component. This design uses nine PPTCs in different branches to achieve overcurrent and over-temperature protection. Compared to the traditional solutions discussed in the background, this is equivalent to requiring nine sets of traditional protection schemes, resulting in over 300 components to achieve the same protection function. Furthermore, these components cannot be 100% reliable or 100% stable. The cumulative errors of the components and the distributed parameters of the circuit layout may interact to generate resonant high voltage, causing individual components to fail and short-circuit, leading to quality disputes and reputational damage. Moreover, the PCB area occupied may exceed [a certain value].

[0049] The energy consumption of PPTC1-PPTC9 is 300 times that of PPTC1-PPTC9, its energy loss is more than 100 times that of PPTC1-PPTC9, its component cost is more than 200 times that of PPTC1-PPTC9, and the costs of engineering design, layout, debugging, production testing, soldering, auxiliary materials, after-sales maintenance, and market maintenance are incalculable compared to the automated production of PPTC1-PPTC9. Therefore, the reliability and stability advantages of using PPTC1-PPTC9 are evident, and its service life is unmatched by traditional protection solutions. It not only simplifies the overall circuit design but also solves the problems of component damage and short-circuit current limiting protection. It can also provide both human-caused and non-human-caused short-circuit protection for the aforementioned circuit system, preventing circuit burnout and serious fires caused by short circuits. It also solves the design problems of related equipment manufacturers and engineers, using the fewest components, occupying less space, with lower cost and higher reliability, making the product safer, simpler and easier to design, providing genuine safety assurance for related equipment, and directly enhancing the market competitiveness of manufacturers.

[0050] This portable karaoke machine primarily functions as a song selector, song skipper, progress display, simultaneous video and audio output, internal recording (with a built-in 2TB or 4TB digital hard drive, pre-stored with over 100,000 karaoke songs), and a multi-track music reader. For different application scenarios, optional features include: Bluetooth connectivity for mobile phones, a built-in high-quality speaker, AUX output for external speakers, wireless microphone input, mobile phone QR code song selection, reverb adjustment, HDMI high-definition data output, connection to projectors and TVs, VGA interface for connecting to computer monitors or projectors, original sound / accompaniment / music reading / singing / technique sheet music follow-along, fiber optic communication interface, WIFI communication, and effects output.

[0051] The embodiments described above are merely illustrative of several implementations of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. A portable KTV karaoke machine circuit based on a PPTC self-resetting fuse, comprising a power input interface (K1), a charge / discharge management circuit, a lithium battery, a power conversion circuit, and multiple functional modules, characterized in that: A first self-resetting fuse (PPTC1) is connected in series between the power input interface (K1) and the charge / discharge management circuit; A fourth self-resetting fuse (PPTC4) is connected in series in the charging and discharging circuit of the lithium battery; Multiple self-resetting fuses (PPTC2, PPTC3, PPTC5-PPTC9) are connected in series at the output terminal of the power conversion circuit, the power input terminal of each functional module, and the output circuit of a specific functional module.

2. The mobile KTV karaoke machine circuit according to claim 1, characterized in that, A varistor (RV) is also connected in parallel at the rear end of the power input interface (K1). The varistor (RV) works in conjunction with the first resettable fuse (PPTC1) to achieve overvoltage protection.

3. The mobile KTV karaoke machine circuit according to claim 1, characterized in that, The multiple functional modules include at least one of the following: MCU and encoding / decoding circuit, LCD screen and driving circuit, touch screen and driving circuit, audio power amplifier circuit, I / O and interface driving circuit, Bluetooth circuit, and storage module.

4. The mobile KTV karaoke machine circuit according to claim 3, characterized in that, The third self-resetting fuse (PPTC3) is connected in series in the power path of the USB interface.

5. The mobile KTV karaoke machine circuit according to claim 3, characterized in that, The fifth resettable fuse (PPTC5) is connected in series in the power path of the touch screen driver circuit.

6. The mobile KTV karaoke machine circuit according to claim 3, characterized in that, The sixth self-resetting fuse (PPTC6) is connected in series in the power path of the LCD screen driving circuit.

7. The mobile KTV karaoke machine circuit according to claim 3, characterized in that, The seventh resettable fuse (PPTC7) is connected in series in the power path of the audio power amplifier circuit.

8. The mobile KTV karaoke machine circuit according to claim 3, characterized in that, The eighth resettable fuse (PPTC8) is connected in series in the power path of the I / O and interface driver circuit.

9. The mobile KTV karaoke machine circuit according to claim 3 or 7, characterized in that, The ninth resettable fuse (PPTC9) is connected in series in the circuit between the tweeter and the audio amplifier circuit.

10. The mobile KTV karaoke machine circuit according to claim 1, characterized in that, The resettable fuses (PPTC1-PPTC9) are surface mount packages.

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